An H-pattern manual transmission uses an H type movement of the gear selection lever while a sequential transmission works with upward and downward movement of the lever, to shift between the gears.
Sequential gearboxes are simple. If a user wishes to shift from second to third gear, this can be achieved by a simple upward push of the gear lever. In a manual transmission, a user is required to move the lever up, around and up to complete the same task.
Sequential gearboxes have consistent shift patterns. If a user wishes to shift gears up or down, they would use the same movement. A user does not have to think about the movement pattern to perform the action as is the case with H-pattern manual transmission systems.
With sequential gears, hand placement and movement are always the same. In case of an H-type manual transmission, a user always has to think about the location of gear lever with reference to the current gear and desired gear. A sequential transmission shifts gears by upward or downward movement. Response times are relatively less with sequential transmissions.
There are fewer missed lever movements with a sequential gearbox. A user cannot accidently shift the wrong gear and damage the transmission. If a user were using a manual H type gearbox, they can accidently shift up when they wanted to shift down. This cannot happen with sequential gearboxes.
Sequential shifters are known. U.S. Pat. No. 6,308,797 relates to a shifter for a motorcycle transmission. This patent depicts the common barrel cam used in motorcycles and deals with solving the problem of positively stopping the barrel cam in incremental gearshift positions. This ratcheting mechanism does not positively control the barrel cam throughout movement, but does include a stop at end of incremental movement. If for instance the cam is partially moved, due to accidental movement of the motorcycle rider's foot, the ratchet mechanism will disengage the cam in an intermediate position. In addition, if the rider's foot motion is not uniform and slows down toward the end of shift motion, the cam can move inertially past a shift position. In addition, if the gear teeth or engagement dogs in the transmission do not smoothly engage; actuation force increases rapidly, resulting in stored energy within the mechanism, the rapid release of stored energy can cause the cam to spring away from the ratchet assembly, and result in uncontrolled cam movement.
The ratcheting system patented in U.S. Pat. No. 6,843,149 B2 closely resembles and has the same inherent limitations as the ratchet system used in U.S. Pat. No. 6,308,797. U.S. Pat. No. 6,843,149 B2 relates to a sequential shifter for an automobile transmission. This patent depicts a mechanism for mounting on a transmission to provide sequential gear selection by using: “One or more disk cams arranged to be turned by a rotary motion and a follower for each cam adapted to produce to and fro movement capable of linkage to a gear train selector.” In this embodiment, separate cam active surfaces are required for each follower. In this patent, the ratchet mechanism does not positively control the cam during movement.
These mechanisms are sequential and are not intended to adapt an H-pattern transmission to a sequential shifted transmission. Adapting an H-pattern transmission to a sequential shifted transmission means that the advantages of a sequential shifted transmission can be gained in a vehicle that may have an H-pattern transmission without requiring replacement of the entire transmission.
It will be clearly understood that, if a prior art publication is referred to herein, this reference does not constitute an admission that the publication forms part of the common general knowledge in the art in Australia or in any other country.